Jtekt Corporation

Akiyoshi Tashiro

Katsura Koyagi

Yasuhiro Yukitake

Hiroki Kagawa

Hirofumi Dodoro

Naoko Sakaguchi

Takafumi Uemoto

A ball screw device includes a screw shaft; a nut having a second helical groove; and a plurality of balls. When the screw shaft is rotated about an axis of the screw shaft while being subjected to the external force, the balls are displaced from positions under no load condition toward one side in an axial direction. A second helical groove of the nut includes a stopping member configured to prevent the balls from falling off from the second helical groove. A plurality of coil springs are arranged in series along the second helical groove. An angle in a circumferential direction occupied by each of the coil springs about the axis is 180 degrees or less when the coil springs are disposed in the second helical groove.

Ball screw device

A ball screw device includes a screw shaft, a nut, a ball train including a plurality of main balls, and a plurality of coil springs disposed in the ball train. The nut moves from a first axial side to a second axial side while an axial force is applied to the nut by rotation of the screw shaft. The plurality of coil springs are more densely arranged on the first axial side than on the second axial side in the ball train.

A ball screw apparatus includes a ball nut through which a ball screw shaft is inserted. A recessed portion is formed in an inner periphery of the ball nut and is recessed so as to extend in a tangential direction of a ball track. A ball train including a plurality of main balls and a coil spring are housed in a raceway. The recessed portion includes a first surface that supports a second end of the coil spring via a stopper ball and a second surface that regulates movement of the stopper ball in a nut axial direction. The second surface is inclined by an angle corresponding to a lead angle of the ball track of the ball nut from an axially perpendicular plane of the ball nut so as extend in the direction of the lead angle.

Ball screw apparatus

A ball screw device includes a cylinder that surrounds the outer periphery of a ball nut. Accommodation holes are formed in the ball nut at a rolling start position and a rolling end position in ball rolling paths. An outer periphery turning groove is formed in an outer peripheral face of the ball nut, and the outer periphery turning groove and an inner peripheral face of the cylinder constitute a turning rolling path. The turning rolling path and connection passages formed in deflectors constitute a circulation path through which balls are returned from the rolling end position to the rolling start position.

A transmission that is able to perform shift operation and select operation using the driving force of a single electric motor is provided. A shift/select actuating device includes: an electric motor; a first conversion mechanism; a second conversion mechanism; and a changing unit that changes a destination, to which the rotational driving force of the electric motor is transmitted, between the first conversion mechanism and the second conversion mechanism. The changing unit includes: a first electromagnetic clutch that transmits the rotational driving force of the electric motor to the first conversion mechanism or interrupts the rotational driving force; and a second electromagnetic clutch that transmits the rotational driving force to the second conversion mechanism or interrupts the rotational driving force.

Growing community of inventors

Yamatotakada, Japan

Akiyoshi Tashiro